1 files changed, 90 insertions, 0 deletions
diff --git a/js/src/gdb/mozilla/Interpreter.py b/js/src/gdb/mozilla/Interpreter.py
new file mode 100644
index 0000000000..825ae40e9d
--- /dev/null
+++ b/js/src/gdb/mozilla/Interpreter.py
@@ -0,0 +1,90 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Pretty-printers for InterpreterRegs.
+
+import gdb
+
+import mozilla.prettyprinters as prettyprinters
+
+prettyprinters.clear_module_printers(__name__)
+
+from mozilla.prettyprinters import pretty_printer
+
+
+class InterpreterTypeCache(object):
+    # Cache information about the Interpreter types for this objfile.
+    def __init__(self):
+        self.tValue = gdb.lookup_type("JS::Value")
+        self.tJSOp = gdb.lookup_type("JSOp")
+        try:
+            self.tScriptFrameIterData = gdb.lookup_type("js::ScriptFrameIter::Data")
+        except gdb.error:
+            # Work around problem with gcc optimized debuginfo where it doesn't
+            # seem to be able to see that ScriptFrameIter inherits the
+            # FrameIter::Data type.
+            self.tScriptFrameIterData = gdb.lookup_type("js::FrameIter::Data")
+        self.tInterpreterFrame = gdb.lookup_type("js::InterpreterFrame")
+        self.tBaselineFrame = gdb.lookup_type("js::jit::BaselineFrame")
+        self.tRematerializedFrame = gdb.lookup_type("js::jit::RematerializedFrame")
+        self.tDebugFrame = gdb.lookup_type("js::wasm::DebugFrame")
+
+
+@pretty_printer("js::InterpreterRegs")
+class InterpreterRegs(object):
+    def __init__(self, value, cache):
+        self.value = value
+        self.cache = cache
+        if not cache.mod_Interpreter:
+            cache.mod_Interpreter = InterpreterTypeCache()
+        self.itc = cache.mod_Interpreter
+
+    # There's basically no way to co-operate with 'set print pretty' (how would
+    # you get the current level of indentation?), so we don't even bother
+    # trying. No 'children', just 'to_string'.
+    def to_string(self):
+        fp_ = "fp_ = {}".format(self.value["fp_"])
+        slots = (self.value["fp_"] + 1).cast(self.itc.tValue.pointer())
+        sp = "sp = fp_.slots() + {}".format(self.value["sp"] - slots)
+        pc = "pc = {}".format(self.value["pc"])
+        return "{{ {}, {}, {} }}".format(fp_, sp, pc)
+
+
+@pretty_printer("js::AbstractFramePtr")
+class AbstractFramePtr(object):
+    Tag_InterpreterFrame = 0x0
+    Tag_BaselineFrame = 0x1
+    Tag_RematerializedFrame = 0x2
+    Tag_WasmDebugFrame = 0x3
+    TagMask = 0x3
+
+    def __init__(self, value, cache):
+        self.value = value
+        self.cache = cache
+        if not cache.mod_Interpreter:
+            cache.mod_Interpreter = InterpreterTypeCache()
+        self.itc = cache.mod_Interpreter
+
+    def to_string(self):
+        ptr = self.value["ptr_"]
+        tag = ptr & AbstractFramePtr.TagMask
+        ptr = ptr & ~AbstractFramePtr.TagMask
+        if tag == AbstractFramePtr.Tag_InterpreterFrame:
+            label = "js::InterpreterFrame"
+            ptr = ptr.cast(self.itc.tInterpreterFrame.pointer())
+        if tag == AbstractFramePtr.Tag_BaselineFrame:
+            label = "js::jit::BaselineFrame"
+            ptr = ptr.cast(self.itc.tBaselineFrame.pointer())
+        if tag == AbstractFramePtr.Tag_RematerializedFrame:
+            label = "js::jit::RematerializedFrame"
+            ptr = ptr.cast(self.itc.tRematerializedFrame.pointer())
+        if tag == AbstractFramePtr.Tag_WasmDebugFrame:
+            label = "js::wasm::DebugFrame"
+            ptr = ptr.cast(self.itc.tDebugFrame.pointer())
+        return "AbstractFramePtr (({} *) {})".format(label, ptr)
+
+    # Provide the ptr_ field as a child, so it prints after the pretty string
+    # provided above.
+    def children(self):
+        yield ("ptr_", self.value["ptr_"])